JPH0113860Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a load brake that uses magnetic powder to prevent the rotating shaft from overrunning when the rotating shaft is stopped.

For example, rotating shafts used in devices that require high accuracy in stopping position, such as the document table reciprocating mechanism or paper feeding mechanism of a copying machine, are required to stop without overrunning when the power is cut off. Ru.

This invention provides a load brake using magnetic powder that meets the above requirements, and includes a hub made of non-magnetic material that is fixed concentrically to the rotating shaft, and bearings for supporting the rotating shaft placed on both sides of the hub in the axial direction. an annular permanent magnet that is fitted and fixed to the outer periphery of the hub; and a sealed case in which center holes in both end walls are fitted to the both bearings to form a sealed space between the hub and the permanent magnet; It is characterized by comprising a felt ring attached between the inner surface of the end wall of the sealed case and both end surfaces of the hub, and magnetic powder particles loaded between the inner surface of the sealed case and the permanent magnet. There is.

Next, the load brake of this invention will be explained by way of an example with reference to the drawings.

The drawing shows an embodiment of the load brake of this invention in a side view of the upper half of the load brake. As shown in the drawing, the load brake of this invention includes a hub 2 made of a non-magnetic material fixed concentrically to a rotating shaft 1, and bearings 3, 3 for supporting the rotating shaft arranged on both sides of the hub in the axial direction.
, an annular permanent magnet 4 fitted and fixed to the outer periphery of the hub 2, and both end walls 5A, 5B attached to the bearings 3, 3.
A sealed case 5 in which the central holes 6A and 6B of the hub 2 and the permanent magnet 4 are fitted to form a sealed space A between the hub 2 and the permanent magnet 4, the inner surfaces of the end walls 5A and 5B, both end surfaces of the hub 2, and the bearings. 3, 3 flange parts 3A, 3A
and magnetic powder particles 8 loaded between the inner surface of the sealed case 5 and the permanent magnet 4. It sticks to the equipment frame, etc.

The rotating shaft 1 and the hub 2 are fitted with serrations, and the hub 2 and the permanent magnet 4 are bonded together.
It may also be by other fixing means.

Further, the bearing 3 is made of tetrafluoroethylene, and the sealed case 5 is made of a magnetic material.

In the load brake of this invention having the above-mentioned configuration, the magnetic powder particles 8 within the magnetic field of the permanent magnet 4 connect the permanent magnet 4 and the sealed case 5. When a torque is applied to break the bond, the rotating shaft 1 rotates.

When the torque transmission to the rotating shaft 1 is interrupted, the rotating shaft 1 instantly stops without overrunning because the permanent magnet 4 and the sealed case 5 are integrated by the magnetic powder particles.

The hub 2 and felt rings 7, 7 are made of non-magnetic material so that the magnetic flux Φ of the permanent magnet can pass most effectively between the end surfaces of the permanent magnet 4 and the end walls 5A, 5B of the sealed case 5. This is provided in order to obtain a stable bonding force due to the magnetic powder particles 8.

Furthermore, since the bearings 3, 3 are made of tetrafluoroethylene, there is no risk of adverse effects on the magnetic powder particles 8 unlike in oil-impregnated bearings, and troubles such as seizure do not occur.

As is clear from the above explanation, the load brake of this invention has an extremely simple structure, but it can stop the rotating shaft instantly and without overrun when torque transmission to the rotating shaft is interrupted. Has excellent advantages.

[Brief explanation of the drawing]

The drawing is a longitudinal cross-sectional side view of the upper half of an embodiment of the load brake of this invention. In the drawings, 1... rotating shaft, 2... hub, 3... bearing, 4...
...Permanent magnet, 5... Sealed case, 5A, 5B...
End wall portion, 6A, 6B...center hole, 7...felt ring, 8...magnetic powder particles, 9...mounting plate.

Claims (1)

[Scope of utility model registration request] A hub made of a non-magnetic material that is fixed concentrically to the rotating shaft, bearings for supporting the rotating shaft arranged on both sides of the hub in the axial direction, an annular permanent magnet that is fitted and fixed to the outer circumference of the hub, A sealed case that fits into the center hole of the wall to form a sealed space between the hub and the permanent magnet, and a felt ring installed between the inner surface of the end wall of the sealed case and both end surfaces of the hub. and magnetic powder particles loaded between the inner surface of the sealed case and a permanent magnet.